Ammeter



1943- A. H; WOQLFERZ ET AL 2,326,909 I AMMETER Filed Feb. 10, 1940 3 Sheets-Sheet l EjvwcMMdl 16 w f I v 11%,

{my/"M 6.

Aug- 17, 19 3- A. H. WOL-FERZ ET AL 5,

v AMMETER Filed Feb. 10, 1940 3 SheetsSheet 5 sign practice.

m wi 531 eave ms a centa' tz i the'socket.

'I'he instrument assemhly is removable as a unit from the socket and includes azpair or hollow terminals I! for engagement with the socket 5 pin terminals l6 when the instrument is placed, .in the sogket. measuring; within. t flia iil i m y befl any d sired de i n but preferably is of the sensitive direct current 'silijent indezt arm 31' engages'slotsor recesses 38 i in the base 22 to facilitate the adjustment of the" switch to its several positions.- The angular movement of the switch blade is limited by the engagement of a lug 39 of the index arm 31 with 'the ends of a-slot or recess lflein the base-22..

:Amlurality of resistamesi mm Tthe form or w nding -lawman metal terminal flanges; are mountedon certain of the'switch :milliammeter'Qa-nd rectifier bridge type thatj isj,iQgzontactgBB and internally threadedrbushings'. 42

shown diagrammatically in Fig.3]. ThereSistOrs I8 oi the rectifier bridge are connected tomml 1 mounted on a studl9 thatigxtendsmthrough gul -8 that are molded into the'base 22. The contacts and bushings 42 are-of identical design, and ,thegresistance spoels or conducting strips are .fto sage inserts by small screws, see

the bridge are within the; smalldgeusjng unit ig i;5iEi sfliimd fi: !Ihe measuring circuit that-is that is mounted on the .b'ase 3; The moving coil 2| of the milliammeter is pivhtally supportediinthe field of the permanent magnet 'Tl and'is connected to the rectifier bridge in illsilfil", manne ,f fh f tr cal c rcu o th imitrw -ment is shown infigfi and the physicalstructure f the instrument may conform to gmjdderange-changing systernpf the instrument assembly; as shown-f'inffigs; 4 and "5; ecrnn'rises a basefl of insuiatingmateriarhaving openings ,23 for receiving screws? "for securing jthejaase 22 "to jhe 1hase of Ethemilliamnieter. fThiefb'ase 22 has-other openings for passing the terminals ndr he' us a cmi ast d 'fif h tt "3 V gages the contaotship ,H, Fi g'fifs, to iseparate -i t ='frjom cont act tr es wnen'tninsm enta semblyisfplugged intp thesocket. fiie auxiliary phase '22 also carries :aicentrallylocated screw fi fpr engagement igy aflthread dbpshing iron-the 3 Are'ar wall cf th-e sdcketsection 2 to clamp the-instrum'entin plaee wlthinthe socket.

xilfhejauxiliary base 22 has asemi-jcircular -flan ge agt ithe upperpartgf its 'iront facefto space semi-1s a ertured to provide a for the "'gs'witch 1 the range changin g system a idpthe iither bearin'gfcoinprlses a mlindricalfrecess in shownzschemlitically'in Fig. 7 is established by c Qnductingstrm, that is secured to the bushj fing #toffanendresismr 4| and has an apertured r gdgiiorjgfitting upon oneof theterminals H, a conducting strip 44 ;t hz a,t; is secured to a, contact ih wmi e i er t:ith f mflewb se H and has anjaperturcd seatingpnihe stud l 9 ,'and an extension ii ofth'e switch" '35 lim s a ur f fit r 'i e h i' ermi 5 s' i ria r TQfh WI ma i iTEnEEE t socket; "terminals i6 itowcnneqt the tcpmpigt i pomt nemoteffremthe bablcprconductpr thatfls socket-of t knoldedfbccly section- 2 when thejlnstr-ur'nent-: range changing assembly is The socket element eomprises"allboigf lravdng' a i {cover {flij with a en-circular 'openingdl 'fiorrej b l ma m t Qf t ni of A5 ceiving t-he instrument-switch 1111117, and carrying c "the 'handle-transiormer assembly; lhe exten a mnge scale n dupiicating the {scale}! on the melded bodylefthe hanmfimne me assem are-flan e or instljiment ca'se s {orreceiying the conductbrsfi a c b e:flarezco i ectediand "a.

fshaltt 2g of theswitch. A sleeve not insulatin material is melded upon'the shaft 15,131( literatihates in a handle -3'l that is positioned'fior' reafly operatijon by the: thumb "hand:

terating handle {H} The useIulne'ssbf-a pends' upon range of waluestrrai merbe .aiq cmityin eperatm: mngaerclianami swi ches .01 A r v l r be timed at any convenient point when the cable of a clamp-on'ammeter will gsgg llyhavegmiymfi hee ire? tee he h l cat nr strilment switch unit to seem-e the sam'eiwithin the bex; plug 50 at -the dther end, 01 cable 49 has a non-circular cross section'fqr flttmg 'liandiel 1;01:1 am tamp-err smmereary ggr and 2. m the socket d m i m n- *1 infla sa e e ans t'wl cs is molded in V orothenvisemarked on the scum": adjaer the extension amt-f upper part re ing contacts ugwwhen the piug is n m -m the socket or section 2 of the transformer handle,

, and a screw 26' for engagementbybushmgs 21 mil. 1 V

The socket element of the mans re ame may "is so locatedrthat it would be diflicult or impossi- V ble forcperator to read'the instru'ment when positioned in'the handle'socket 'rnethod of 7 remote indication withj'a clamp-on ammet'er is P wns is thcjre' e eciim rimpbransea 'ae T0 Entirely Practical: em e I h f range-changing merie tbe pna a siiem bl P by the handle-transformer ass embly thati hung V V M e (1t istobe a time-than. rei 5 am! spaced.co'ritactsffi,respectiwcl'y,anda re 7 swit'cl i is carried'bytheplug-in ammeter and not 5 tude in the designand construction oftheparts .orflthegmeasuringgl apparatusandithat imanyl V changesfthatemay.bemade mtheii ustrated-eme 1 bo'dim'ent falltwithinjth, spiriteofzour 'nvention" as set forthflin thefollowing claims.

; ment,"'a transformer-core including a stationary sectionand i'a pivotallyi mountedqsection, ;awind-- 10f insulatin g mat'er yer 'pivoted onthe socket section'jandnormally section, a transformer core including a station-5 7 an instrument carried by said socket section,- and: I circuit elements connecting said windingito sald instrument.

" in whichthe handle is held.

- comprising a handleanda section for supporting V 'an instrument; a transformerv mounted on: saidl body portion and including'af stationary and a ary section of the transformer core, an instrument carriedeby said instrument-supporting sec-- winding to said instrument; said range-changing 4:3

comprising a handleian'd aninstrument-supportring section, a transformer core supported on said;

' i one of said core members, contacts carriedby means adapted to bemounted on andremoved v from said instrument-supporting section'of the ing terminals for engagement Withsaid transapparatus is'inserted into. said socket section.

1 section and; measuring apparatus, adapted; to be and h ndle;.mere ntq a ock iWe claim'ze. V. x1; a.clamp.-on' ammeter ameasur f 31 35 m? mea urin p i r t h i ::F? Tm l$ 'terminals when said measurin 1 v ten ed int rsa dac e l ee i e.c an nr am ie su ating-1- ,Qet ri surmr i e a s t t nsai m ;qe n i.a henq me emj .mi ia ei ing on thegstationarysection oi gsaid core, aflbody V comprising a handle pjor-s tion merging; into a -supporting portion"that-car; ries a said. transformer core and saideins'truinent'; and ffci cult 1 elements i'including range-changing; 7 i means connecting said-instrument to said 'wind for actuation by thethumb'of'th hand inwhich j-f V t V r the handle is held. Y." j 531 :m as m pp at comprislngap g ele- 2. In aclampeon. ammeter, a moldedbodyj socket section surmounted by a top-section, arle positioned-within a slot in the edge off the socket; i

-' ofsaidjsocket member.

-9.;In a ,clamp-on j'ammeter; a molded body -member of insulating material supporting a split bodyportion and a sectionmounted on thel'ever; a Winding on thestationary section of said 'core,

. p m i'nginto asocket section-,-a windingon th tr n 3; In a clamp-on ammeterpthe invention as claimed inclaim 2, wherein said leverincludes v V a trigger extending' along the upper portion of 3 e dl g t0 Sh 0rtc1rcu1t said windthe handle in position to be encircled by thehand mg SU-D pp atus including an. element 35 with terminals for engagement with said wind- 4.'In a. lamp-on ammeter, a body member movable core section, a Winding on the stationin n 3" clalfnpron m e the vention as I V claimed n claim 9, whereinrsaid measuring apincluding rangechangingmeans connecting'said C Wm n s- .i g Y t v 1a la p-0n ammeter, the inventionas,

meansiincluding a switch havingan' operating member positioned for actuation by the thumb of the hand in which thehandle is held. j

5.In a, c1amp-on ammeter, a body member 7 V bodymember and comprising a stationa y member, and a pivoted core m m awinding 0n ijwith a body member carrying a'vsplit transformer core and a'winding on said core'saidrbody-memsaid instrument-supporting section and v connect-f ed to said Winding, and measuring instrument i nals connectedto" the ends of said winding a body member, said measuring instrument means said assembly-including" an ammeter'within a tacts when said measuring instrument means is v v N s a switch base mounted on said amm t mountedion said instrument-supporting section of saidbody'member, J

6. In a clamp-on ammeter', a body portion of a 1 blade means r e a ing said contacts. 7. V

n a multi-rangeammeter, the combin'a -tion with antarnmeter Within a case" andthr ee tion, and measuring apparatus including plug-in from said socket section','said plug in means havfomer winding terminalswhen saidQmeasui-ing -insu ati :mate el 'siln b tins az plitfit a isr ndingonthfil ransformer coreptere V ins te n dremved; 1 1011.11 saidfibek t s c-- forf engag'ement gwith said transj rmgg qm j g appara u is;

i erat s, o T

ec ion: w ding i lie?- iran f mer, 991e t ing; said 'Iang8-1-Changingfmean v-includjng a '15 minals forsaid winding carried by said socket witch having" an 'operatingjmember positioned v isection and measuring apparatus adapted to be connected to saidtransformer winding terminals;

I nientfto beginserted injsaid socket section and j member comprising a',-handle merging into-"a at)" having terminals for engagement with th 1; v

' formerwinding terminals, asocket member hayinggterminals'connected'by a cable with=theterminals'; ,of saidplug element; 1 and 'ameasuring instrument meanspositioned'in saidsocket mema ary section supported by the top section of thef nd a i a terminals ng the terminals transformercoreand including a handle merg-' .former'core,;terminals for said'winding carried by the socket section;resilient contact strips on fi ing terminals when plugged into'said socket sec-f :tion, andapin on said element 'for separating said contact strips when plugged intosaid soek paratuscomprises an amm eter constituting said tiontqf said body memberfandcircuit elements element havmg terminals for engagementwith' 1'2. Ina c m e e e'combination' ber includinga socket carryingfapair of termi- Y unitary ammeter and range-changing switch having terminals for engagement'with-said con-' ly adaptedto be plugged into i socket? ease, rangegadjusting resistors mounted on said I 7 "base, switch contacts on said base and connected insulatingmaterial supporting split-transformes to Said or a u a ya iu Switch 1 ver core d}; handle merging into a socket sec- 7 men, a Winding on the-transfo r core, te -J:

7 H918 f r-said ding earrie'd by said socket sec I V v terminal members carried by and projectingffr om means adapted to be inserted in and removediqo the backeof said case said ammeterbeing'con 1 nectedjbetween a pair of said'terrninal members, 1 v of range-changing ;means for said am'meter; said range changin'g v me'ans comprising a; base and means for, mounting the same on the back I r 7 7.'In a clamp-on ammeter, a body portion 01.75 offisaidcase;aplurality of resistors' onsaid base i minal member ndone terminal member cf said 14, In a, multi -range'firhmetr, the invent on as recitedin claim '13, wherein said basevihch'xds a flange projecting therefrom gtb engage) the f I of said case, and t-herebyjsp'ace {-said base from v the case said swi tch contacts-are at thQ-forward.

said swit 'cfi meanszinniuds 15; In -a multi-rang e an lmeter, thevinyent i on as recited in -c1a.lm 13; whe:e1n said: sire "lfn'ounted on the: rearward face of saidibas e," and? said base hs ai fiange engaging theibnck of; said:

base to?provide aaspacecwbetweenr saith case and:

ii) said in which :saidgswitqhs means 7 :ppsi

tioned; 'fn combination witbacom platesecured: t d said' bas'e :t'd= extend over-said; resistors. 7 H,YWOLFERZ. 

